This site might be interesting if you are wondering about brands and additives, It is sponsored by BMW, General Motors, Fiat Chrysler, Honda, Toyota, Volkswagen, Mercedes-Benz and Audi. It sets a minimum standard and shows the brands that meet this standard.

www.toptiergas.com

http://www.toptiergas.com/

 

I always use Chevron Premium in all 3 of our vehicles. On the RX I have averaged 19.5 mpg so far during its 2700 miles. The price difference isn't much considering.

 

 

Another gas thread.

It is like religion, believe what you want.

My religion on gas is to use a good brand name regular grade in both RX and LX and have never had a problem. In my LX you lose about 2-3 HP as Toyota has the same motor in the Land Cruiser which the recommend regular with 2-3 less HP. When they delivered my LX they filled it up with regular as do most Lexus dealers.

If premium make you feel better, go for it.

 

I wonder about the "or higher". I know the stated HP and torque are at 87 but would higher octane improve performance?

 

No. And higher octanes should give you poorer gas mileage since octane enhancers (such as ethanol) have less energy per volume than the gasoline that they replace in order to increase the octane rating.

 

Most Regular Gas in Albuquerque, NM is 86 Octane, owner's manual sez to use 87 or higher, so I use Premium mostly as Regular Gas does not meet the Owner's Manual requirement... Some gas stations in Oklahoma still sell "Real Gas" without alcohol at a price increase. NM does not have that.

 

I have some knowledge on this subject. you can run either or, of course 91 is better for performance.
Heres why, your computer is monitored by knock sensors to prevent detonation Thats the killer to your motor.
So when you do not have enough octane in the fuel the knock sensers will detect this and adjust your timing.
Timing, fuel/air are the key to HP. Decrease timing, lower HP. That said you will not do any damage to your engine
by running lower octane but you will definitely give up some performance. Keep in mind thar your computer will
only adjust so far so running 91oct gives you the benefit of peformance and gives you a safety buffer in case the
fuel octane is not quite what it says. Hope this helps.

 

Any input on the effect of 85 octane in high altitude areas like Colorado? Regular octane here is 85, which I believe is because of the way altitude affects detonation? I have heard that it operates the same as 87 at sea level but I would like to know from someone with more knowledge than myself.

 

Putting high octane into engine are design for 87 octane will not make performance gain.

 

 

That was super informative! Thanks for posting that! I don't know much about this stuff and I know it has been discussed in length but does it make a difference that it was Chevy vs. Lexus? I know Lexus says that the 350's cars are made to take regular but it makes me wonder if these tests results would be any different on a higher end car. Are they tuned any differently to make them slightly more efficient with the premium fuel?

 

Agree, I wish they would have done the tests over with a vehicle that "required" Premium. That would have been the clincher.

 

Excuse the bad maths

 

I wondered about the line in the owner's manual that said 87 octane or higher was required. So over the last month or so I did 3 weeks of regular fill ups and 3 weeks of premium fill ups. I had 2 regular fill ups and hand calculated 19.4mpg. [Tank was run down to 15 mile range before filling with premium.] I did 2 premium fill ups and hand calculated 22.1mpg. City to highway ratio was hand calculated based on average speed between fill ups to be between 55-60% city.

I also have a wireless OBD II reader that calculates HP and torque. Max HP on regular was 297hp at 6147rpm and 279ft/lb at 4208 rpm. Max HP on premium was 307 at 5742rpm and 297ft/lb at 3630 rpm. Numbers were generated in sport mode by flooring the car while merging onto the highway. Acceleration from roughly from 30mph to 80mph. The car determined the shifts but it appeared to be near redline (~6450rpm).

This wasn't a well controlled experiment but interesting none the less.